President Obama nominated Yellen to serve as chairwoman of the Federal Reserve after Ben Bernanke's term expires January 31. Despite objections from a few Republicans, she is widely expected to be confirmed for the position.

Warren to Yellen: Focus on banks

In a statement released Thursday, Sen. Marco Rubio of Florida said he will vote "no" on Yellen's nomination because of her support for the Fed's stimulus policies. The Fed has kept interest rates near zero and been engaged in controversial bond-buying programs since 2008, in an effort to boost spending.

Rubio believes those policies "put the U.S. economy at increased risk of higher inflation and another future boom-bust."

Yellen needs 51 votes to be confirmed, after the Senate changed its rules for filibusters Thursday afternoon. Previously, she would have needed 60 votes to pass that procedural hurdle.

Either way, the votes don't seem to be a problem. Yellen already has the support of at least six Republicans, and is expected to have the support of most of the 55 Democrats in the Senate.